construction as well as the maintenance of the locks; apart from that it
accelerates the speedy passage of the vessels through the locks.
A rotating type of gate, according to a design by Cˇábelka, is shown
in greater detail in Fig. 11.11. The lower edge of the upright gate is suffi-
ciently submerged at the beginning of the lock filling below the lowest tail-
water level so that the inflowing water is not aerated. For larger heads (up
to 12 m) a similar gate design can be used, but it is necessary to separate
the substantially deeper stilling basin below the gate from the lock
chamber proper by a concrete screen. The installation of this type of gate
is considerably eased by floating it into its position; this is made possible
by the two horizontal tubes forming an integral part of its structure, which
LOCKS 479
Fig. 11.9 Filling systems of locks (Novak and Cˇábelka, 1981)
Fig. 11.10 Lock gates for direct lock filling (Cˇábelka and Gabriel, 1985)